


Karma's Lesson

by EtherealNinja



Category: Assassination Classroom
Genre: M/M, Tentacle Rape, Tentacles, Vibrators
Language: English
Status: Completed
Published: 2019-06-15
Updated: 2019-06-14
Packaged: 2020-05-12 02:42:54
Rating: Explicit
Warnings: Rape/Non-Con, Underage
Chapters: 2
Words: 4,003
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19219945
Author URL: https://archiveofourown.org/users/EtherealNinja/pseuds/EtherealNinja
Summary: Koro-Sensei wants to teach Karma a lesson on what happens when his students get too cocky. Forced to comply to protect Nagisa, Karma's body becomes his teacher's toy. Can Karma take his teacher's little "lesson"?





	1. Chapter 1

_This is the worst…_ Karma thought as he clenched his fist at his desk in the back of classroom 3-E. He would have been paying attention to Koro-Sensei's lesson if it weren't for his other idea of a "lesson" that he was giving Karma right now. The thin tentacle was now wrapped entirely around Karma's cock, slowly pumping up and down.

Koro-Senei had called Karma to see him after class one day, and said that he won't get away with his little stunts for free. In return for having destroyed two of his tentacles, Koro-Sensei is allowed to toy with Karma's body however he wants throughout class for the rest of the year. Of course, Karma refused and began to walk out before Koro-Sensei said something the made him turn back. It would either be Karma, or Nagisa. It's up to him. So, fearing for his friend, Karma agreed.

Thank god he sat in the back, where people didn't pay much attention to. Every day, Koro-Senei would sneak his tentacle under the floorboards and up Karma's pant leg. If he tried anything funny, like cutting off the tentacle or hurting it, another would shoot at Mach 20 speed right to the bottom of Nagisa's pant cuff. Only Karma could notice, and he was helpless. He couldn't even skip class.

But right now, Karma was also in a bit of a predicament. Koro-Sensei had been stroking him slowly for two minutes, and he was being driven over the edge. Something was weird with him today, and it might have been due to the cookies the yellow octopus made them that morning. There must have been some sort of drug in Karma's cookie, because he was overly sensitive. He usually didn't let Sensei's little games show on his face, since it just turned the perverted monster on more. But today, it was extremely hard…in more ways than one.

Karma's head was down, and he was leaning towards the desk, panting quietly, a pink flush across his cheeks. Both his hands were gripping the edge of the desk like mad. _Endure it, endure it…_ he thought. He looked up at the octopus with pure killing intent in his eye, but the teacher's cheeky smile only seemed to become more mischievous as he continued his lesson. Nobody noticed yet. However, the tentacle was picking up speed. Once Karma noticed this, his eyes got wide with panic, and he started to reach down to take of the tentacle. But, sure enough, there it was. A tentacle at Nagisa's ankle. He clenched his fists tighter and bit his lip.

Before long, Koro-Sensei was pumping him very quickly. It was getting hard for the boy to keep in his voice. He was a sweating, panting, shuddering, blushing mess in the back of the room, and nobody noticed except Koro-Sensei, who's teaching voice was getting deeper with lust as he watched his young student. Soon enough, Karma felt the building pressure in his abdomen that signified his limit. Unable to hold back, he let out a small noise, a mix of frustration and pleasure, as his climax was building. Nobody heard it…except Maehara. He looked back at Karma, and his eyes got wide as blood immediately shot to his nose, and his dick got super hard. _What the hell is up with Karma?_

"Karma…hey, Karma-kun!" he whispered to Karma. Karma lifted his head and looked at Maehara with a hooded, lust-filled eye. Panting, he contained his rush and smiled sweetly, beads of sweat on his forehead. Maehara did not know what was going on, but Karma looked beyond sexy right now. I mean, usually he looks hot, but his expression, blush, and the way he was bent over the desk, gripping the edges, was too much. "Are you feeling okay? You look like you have a fever…"

Panting, Karma managed to respond to his classmate with a smile still on his face. "Im fine, Maehara-kun, it's just a bit hot in here-Ahh." The tentacle split in two and the other half had reached down and stroked Karma's asshole. His eyes got wide and he released one of his hands to cover his mouth. He bent his head over and closed his eyes, desperately trying to stay controlled. Raising his head, he smiled at Maehara again. "Thanks for your concern though."

"It's nothing…" Maehara responded, slowly turning back around. His fantasies began running wild. He thought he was straight, but seeing how damn sexy Karma looked, _he_ wanted to be the one to make him look that way. I mean, he usually has a cool, composed, mischievous look on his face. And, it wasn't really any hotter in the classroom than usual. Soon, Maehara began to hear small moans coming from behind him. He turned slightly to look at Karma from the corner of his eye, and practically came himself. Karma had one hand between his legs, gripping onto the seat of the chair, and the other was covering his mouth. His eyes were squeezed shut, and he was shuddering and panting. Soon enough, he stiffened up, and then relaxed. Maehara had no idea what just happened. _What in the world is wrong with Karma today…_ Karma was now panting heavily, both hands on the desk again, as if trying to regain his breath. Suddenly he looked up, and shot a death glare at Koro-Sensei. Maehara turned, and looked up at their teacher. He was looking back at Karma, with his book covering a wide smirk. Maehara could still hear Karma's heavy breathing. _Something is definitely going on between them right now…is Karma trying to assassinate him? If so, why did he look so…flushed?_ Maehara couldn't catch on, so he just continued to listen to the octopus, silently willing his erection to disappear.

 


	2. Chapter 2

"Alright kids, you're going to be doing cardio training exercise today, in a not-so-friendly game of sharks and minnows. For the minnows to win, at least two kids have to make it across the forest of 'sharks'." Karasuma declared to class 3-E.

"And amongst the winners, ONE student may have the opportunity to try to assassinate me tomorrow in a confined space for 5 minutes." Koro-sensei chimed in, reclining on a lawn chair and fiddling with a small electronic device that _almost_ every student happened to disregard.

Everyone in the class seemed excited enough for the interesting game as Bitch-sensei split them up into teams…well, everyone except Karma. While he was doing an exceptional job at hiding it, Karma was feeling slightly hot and bothered by the remote-controlled vibrator currently wrapping around his throbbing member. The deal for today was that Koro-sensei got to play with Karma's body for the entire gym class, or Nagisa gets taken out of class early for a special "medical examination."

"Karma-kun, we're both minnows!" Nagisa smiled sweetly as he walked over to Karma with his hand extended for a high-five. Karma shook his head and focused his eyes on Nagisa, trying to ignore the very slight vibration that Koro-sensei had been giving him for the past 30 seconds. He returned the high-five and tried to put on his usual cocky smile. Beads of sweat were emerging on his flushed face.

"Hell yeah. We got this."

"Sharks! You have 1 minute to take your positions in the forest! I suggest you strategize AS you move! Now go, go, go!" Karasuma's voice boomed as half of the young assassins leapt and bounded out of sight.

Karma stood next to Nagisa and the other minnows as they waited for their cue to begin running for their lives across the forest. He had actually gotten quite used to the mildness of the constant vibration, so it wasn't too unbearable.

"Karma-kun~" Koro-sensei's mischievous voice sang from the lawn chair. The redhead turned to glare at his teacher. "Just remember, at least two of you need to make it across, so you may want to revise your usual habit of riding solo for today…" Karma met the gaze of the tentacle monster; determined golden orbs aligned with the teacher's lustful, beady eyes. _That horny pervert doesn't want me to get any privacy as he toys with me, does he?_

"Ya sure you wanna be giving advice to me, you yellow fu-nngh!" Just before he could cuss out his teacher, the intensity of the vibrations increased rapidly, forcing Karma to double over, one hand shot up to cover his mouth from moaning while the other rested on his knee for support.

"Karma-kun?" Nagisa placed a hand on Karma's back as he looked down at his friend in concern. "What happened? Are you okay?"

"Y-yeah I'm fine. Hamstring's cramping up." Karma tried to reassure Nagisa as naturally as possible, pretending to massage his hamstring. "Man this-aah, training, is really working out my-nngh, my muscles." Koro-sensei was playfully alternating from soft to intense vibrations, making it impossible for Karma to not react. A light "fu fu fu" of conceited laughter could be heard from the aroused teacher. Karma lowered his gaze to face the ground, unable to contain his flushed expression as he squeezed his eyes shut and sexily bit his lip. His red hair hung down, shielding him from the slightly curious eyes of his teammates.

"Ehhhh? I thought the training was too easy for you, book boy?" Terasaka teased, completely oblivious to the fact that Karma was lying.

Koro-sensei then stopped oscillating the vibrations and just left it on high, making Karma tremble and whisper an inaudiable "Ugh..fuck…"

Feeling empowered by Karma's lack of response, Terasaka tried to egg him on more. "Hmm..awfully quiet are we now…." But was quickly cut off by Karasuma's shout.

"10 seconds!"

The vibrations stopped entirely. Karma, still bent over, took some deep breaths before slowly straightening up, Nagisa's hand still on his back. He looked straight into Koro-sensei's eyes with as much rage has he could muster in one glance. Koro-sensei's message was clear: Karma was not allowed to be alone during the game. He needed to always be in the line of sight of his teammates as Koro-sensei had his fun. _That bastard._

"Alright minnows, run!"

The small team of young assassins jumped into the forest, with Terasaka, Maehara, Nagisa and Karma seeming to form a small sub-unit.

They ran for a good minute before a paintball bullet shot past Maehara, missing his ear by a millimeter. "Fuck! It's probably Chiba!" The team all dived into nearby bushes or behind trees, hiding until they could determine where the shots were coming from.

"He's up in a tree about 20 meters back. Since he's close we need to move now. We might not get so lucky with his next shot." Nagisa whispered, and all four of them got down and began crawling on their stomachs to a nearby clearing — a location that was out of the range of Chiba's scope of vision.

As all four boys crawled, Karma's stomach dropped as he began feeling the vibrator turn on again, and very slowly get more and more intense. He was crawling behind Nagisa and Maehara, but in front of Terasaka, so he needed to keep moving. Due to his previous arousal before the game started, Karma very quickly found it hard to contain himself as he crawled. His clothes brushing up against his hyper-sensitive nipples, and the ground providing a very slight but significant friction against his groin made it impossible for him to keep going. He stopped, again muffling his moans with his hand, curling up slightly off the ground as he fought the urge to make noise.

It wasn't long before Terasaka noticed him. "Karma, keep moving you idiot…the hell are you doing?!" Karma was breathing heavily with his eyes closed, tensing up his body and making small whimpering sounds on the ground. Terasaka genuinely had no clue what was going on, but he knew that if they stood still they didn't have much time before Chiba would get at least one of them. "Goddammit, kid…" Maehara and Nagisa had already made it at this point, so Terasaka got up onto his knees and awkwardly wrapped Karma's arm around his neck. "C'mon Karma. If anyone's going to be able to make a dent in that tentacle monster in five minutes, it's you."

"haAH..Tera…saka…" Karma tried to respond but was forced to bite his lip, it took his all his focus and willpower to get to the clearing without cumming all over his pants. Terasaka's blushed a deep crimson when hearing Karma say his name in the sexiest way he had ever heard. _This kid looks and sounds like pure sex right now, what the hell?_ Terasaka shook away the thought, concluding that he was letting his mind wander a bit too much. Just as Terasaka was able to half-guide half-throw Karma into the space, he felt a red paint pellet smack into the back of his helmet, splattering everywhere.

"Dammit. I'm out. Christ Karma, get a hold of yourself or this team is screwed." He said before walking off to meet Karasuma, still blushing slightly and shouting something inflammatory up at Chiba.

The vibrations slowly died down and stopped. "Karma, what happened? This isn't like you…are you sure you're okay?" Nagisa asked in genuine concern for his friend.

Karma took a few deep breaths and leaned up against a tree, trying to regain himself. "I told you…I'm fine..." He wiped some of the sweat from his forehead. "Keep moving."

The team of now 3 ran forward, making it about halfway through the forest before being ambushed from above by Nakamura, Yada and Kayano. Each assassin began engaging in a 1v1 fight, with Nakamura matched with Karma. However, when Nakamura saw Karma she got a funny feeling in her stomach. He looked beyond sexy. His hair was sticking to his forehead slightly, face blushing, breathing heavily through his mouth. The redhead didn't even bother to assume a fighting stance, standing up straight with his head tilted lazily to look at her with a gaze of pure lust (which in reality was mostly exhaustion).

"W-What, you cocky bastard? Think I'm to weak to be bothered with?" Nakamura tried to contain herself from pushing Karma against a tree and making out with him — he looked so hot.

_Bzzt….Bzzt…Bzzt….._

_"_ Gahh…" Karma closed his eyes and tried to maintain his composure as he felt the small vibrations yet again, lifting his fists up into a fighting stance. He fixed his determined yet struggling gaze on Nakamura. "Wouldn't imagine it…" He gave her a pained half-smirk in an attempt to look like the normal Karma. She rushed him with a knife, an attack that he easily dodged. But then….

_BZZZZT BZZZZT BZZZZT BZZT!_

The vibrations became much more intense. Causing Karma to cry out and drop to his knees, placing his hands on the ground. Nakamura thought this was because her attack surprised him, smirking as she turned to take advantage of the situation. She raised her knife to make a slash across Karma's back before his arm shot out, grabbing her wrist. "WHA—" Nakamura didn't even have time to react before Karma swung his leg back into her ankles, making her topple over and giving him the perfect opportunity to get on top of her and pin her arms down above her head.

He took her knife easily from her fingers, and though he was still sweating profusely and panting heavily from trying to resist the pleasures Koro-sensei was providing, Karma smirked as he playfully drew an X on the front of her helmet. Nakamura could feel the intense vibrations very slightly through Karma's hand, but decided that he must just be struggling to hold himself up. Let's just say, her panties were the furthest thing from dry at the moment. Throwing the knife into the trees, Karma looked up and saw that Nagisa and Maehara were safe too.

The sub-unit left their enemies and ran ahead, with Karma limping slightly. He placed one hand on his abs to make it look like he had a stomachache, and Nagisa fought the urge to ask him if they needed to take a break or stop again.

"Goddammit….fuck…" Karma gasped under his breath as he was finally forced to slow down, eventually dropping to one knee as his climax approached.

"Karma!" Nagisa ran back to his friend. "Come on, I knew something was wrong today. Rest here." Nagisa helped his friend lean against a rock. The vibrations lessened for a moment, allowing Karma to breathe normally for a bit. Maehara looked at him in concern.

"Nagisa-kun, you go ahead. I'll stay here with Karma. With the two of us working together, one of us is likely to make it across. But you….we need you to win.

The shade of the trees combined with Karma's red bangs hanging down made it impossible for Nagisa to see his friend's expression. "Karma, I can wait for you…"

"No." Karma shook his head. "Maehara is right, we can't risk jeopardizing all three of us. Just go ahead. I'll see you at the finish line." He tried to smile confidently at Nagisa, which only made the smaller boy more anxious. Nevertheless, the bluenette reluctantly turned and leapt away into the forest, allowing Karma to lean his head back against the rock. Maehara sat next to him.

The blond ladies' man couldn't help but glance at Karma out of the corner of his eye. Flashbacks from the classroom the other day were coming back, and Maehara felt his own dick get harder. "Karma-kun…I don't know what's going on….but does this have anything to do with why you were acting strange in the classroom yesterday? I feel like something is going on between you and Koro-sensei. You haven't tried to assassinate him in a while either."

"Hm?" Karma tilted his head slightly to look at him. "Just haven't had a good opportunity."

"Oh come on…the Karma-kun I know doesn't sit back and wait for opportunities."

"Leave me alone…" Karma turned away and closed his eyes again, savoring this brief moment of peace. "I'm telling you it's noth—nngh!" The vibrations began again, this time in beat-like intervals. Hard soft. Hard soft. Hard soft. It was unbearable. Koro-sensei knew exactly what he needed to do to drive Karma over the edge. Karma's body immediately tensed up, and he quickly turned away from Maehara and covered his mouth, but it was too late.

"Karma?" Maehara leaned forward. "You okay?" He placed his hand on Karma's shoulder, pushing him back so he could see his face. It was a big mistake. Karma was blushing deeply, a pained expression on his face. He was panting and sweating and almost drooling. Maehara covered his own mouth in surprise. Karma looked into his comrade's eyes in defeat, just waiting for Maehara to call him weird or disgusting or burst out laughing.

Instead, Maehara leaned down towards Karma's face. Karma tried to recoil as much as he could with his back up against a boulder.

"Maehara…kun?"

The blond leaned down until his lips were beside Karma's ear. He breathed heavily. "Karma…are you trying to tease me?"

"Wha-Maehara-kun!" Karma exclaimed as he felt Maehara trail his hand up the side of Karma's thigh, breathing into his neck. Karma tried to turn his head away, but that only made it easier for Maehara to slowly kiss and lick the redhead's pale neck and toned jawline. "The fuck are you-aah! Hnngh!" One of Maehara's exploratory fingers was pressing up against his asshole. Karma's perfect reactions caused him to smirk.

"You're so cute, Karma~" Maehara's free hand snaked up under his shirt, finding his nipple and playfully pinching.

"Nghh, aAH…stop it….wait!" Karma begged. His arms weakly pushed against the slightly taller boy. Maehara took this opportunity to capture Karma's lips with his own, kissing the writhing assassin deeply, making them both moan.

Maehara could feel Karma's soft skin and toned muscles, his body literally quivering and trembling under his touch. Maehara was about to come just from looking at the sexy redhead. Tears were pooling in Karma's eyes. It was overpowering. He couldn't take it. His erection was pulsing with the pleasures of the vibrations, fingering, nipple stimulation and kissing. Karma couldn't resist anymore. His moans got louder and louder as Maehara made out with him. Finally, his mind went blank as he came harder than ever before. He could faintly hear Maehara cum too in his ecstasy. Both boys leaned back, panting and blushing and slowly returning to earth.

"Damn….Karma..." Maehara looked at Karma only to see the redhead covering his eyes, a tear rolling down his cheek. Maehara heard a faint "fu fu fu fu…" of laughter coming from somewhere above them, but when he looked up everything was silent. "I-I'm sorry, Karma. I got carried away-"

"Forget it." Karma started to get to his feet. "Clearly nobody saw us." He began continuing through the forest, with Maehara behind him. Karma didn't experience any more vibrations from Koro-sensei, so they easily dodged all the attacks before both making it across. Nagisa had made it too, and they were the last two there. Nagisa immediately noticed Karma's depressed aura and the tension between his two teammates. Something definitely happened.

"With 3 members across...the minnows win!" Karasuma shouted, making half the class burst into cheers while the others groaned and blamed each other. Suddenly, Koro-sensei flashed at Mach 20 speed into the middle of the crowd.

"Congratulations students! One of the hardest opponents to face are your own friends, and you all fought bravely! I saw many… _wonderful_ performances from you during this training, and as per my deal, one member of the minnow team can face me for 5 minutes! There's no chance that I will run away!" The students burst into cheer and began discussing who to choose. Karma had no interest at this point and he wouldn't be allowed to actually hurt Koro-sensei anyway, so he walked out of the crowd and leaned against a nearby tree. Nobody seemed to notice in the bustle.

"Let's see, have we made our decision?" The class smiled and the noise died down as Nagisa, the designated choice, stepped forward. "Nagisa! I'm SO excited to see what you have in store for me tomorrow!" Koro-sensei shot an evil smirk at Karma, who immediately got a sinking feeling in his stomach. _Dammit! They chose Nagisa?!_ The fear was written all over his face, which only seemed to turn Koro-sensei on more. _There is no way I can let Nagisa be alone with that creep._ Anger welled in his chest as he saw one yellow tentacle draped over Nagisa's shoulder.

 _"_ W-Wait!" Karma came forward. Everyone looked to him, just seeming to remember that he was part of the victor's pool as well. "Please, let me do it." It wasn't usual that Karma would ask for something so genuinely, almost begging them. He tried to smile mischievously, but his face was still plagued with desperation and anxiety. "I've been waiting for this opportunity…" He spun his knife eagerly, proving his enthusiasm. The murmur of the students began again as they all realized that they had forgotten about the best assassin in their class. Nagisa spoke up.

"You'd definitely be a better choice than me, Karma-kun, but what about your health? I thought the training was taking a toll on your muscles."

"I'm fine now." Karma smiled at Nagisa. "Don't worry about me. I got this." The class readily agreed, and after a while Nagisa reluctantly nodded his head.

"Wonderful~~" an evil aura spread from Koro-sensei's grin. "Let's see what you can show me in 5 minutes…Karma-kun~"

All the students began walking back to the classroom, leaving Karma standing in a mixture of fear and frustration. Only Maehara noticed Karma drop to his knees in defeat, cussing softly as he slammed his fist against the ground.

**Notes for the Chapter:**

> ty for reading please leave review ^-^

**Author's Note:**

> ty for reading ^-^


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